PRINCIPLES OF PLANT-TERATOLOGY. 



In the maidenhair tree {Ginkgo biloba) we find 

 abnormally an increase of the number of carpels (here 

 reduced to ovules), which also become long-stalked; 

 doubtless a case of reversion, the normal female flower 

 of Ginkgo being palpably a reduced structure (fig. 106). 



Fig. 106. — Ginkgo biloba (Maidenhair Tree). Female "flower" with 

 five stalked ovules (= carpels). (After Seward & Gowan.) ov, 

 ovules ; spl, carpels ; ax, axis of flower. 



Hermaphroditism. 



Many flowers of monoecious and dioecious plants 

 have become purely male owing to the complete sup- 

 pression of the pistil ; such flowers frequently revert 

 to the original bisexual condition by forming once 



Fig. 107. — Salix aurita. Diagram of hermaphrodite flower shown 

 in Plate XXXVII, fig. 5. (After Velenovsky.) 



more a pistil in their centre. Such occur sometimes 

 in the male inflorescence of the maize. The same 

 phenomenon may be found in willows, e. g. the goat 

 willow (Salix caprea) and 8. aurita (PI. XXXVIII, 

 fig. 5, and fig. 107 in text) ; in 8. caprea Heinricher 



